Some SAA users would file or whittle a notch in the rim of two cartridges so that when lined up they could rest the hammer nose in the opening between chambers, so they could safely carry with six shots at the ready.

That might be necessary with todays .45 Colt cartridges, not with original ones or smaller cartridges. I'm not even sure you would have to do it with modern .45 Colt cartridges.